Update build to use scikit-build-core

[hobu]

scikit-build-core modernizes our builds to allow us to use a pyproject.toml-based build configuration. Other updates in this PR include:

• The version number must be set in two places for releases (unfortunate missing feature of scikit-build-core at the moment is no dynamic version from the Python code)
• Switch to PyPI OIDC Trusted Publisher
• python -m pdal is now a simple command-line utility that prints basic debug info about the library install and the PDAL version it sees.
• python -m pdal --pdal-plugin-dir prints the location of filters.python and readers.numpy Python plugins as installed from https://github.com/PDAL/python-plugins. This can be seen being used in the build/test configuration.